Clone, bootable, back-up, install ML from SL-Help!

I want to install ML from SL. Sorry, but never got around (had time) to do L.
I am knowlegable enough to be dangerous with this kind of stuff; so I'm posting this message is to get confirmation on whether I have it figured out enough to do it myself or should I pay Geek Squad to do it.

I don't know
if I need to delete all the data on the internal drive to install ML
do I need to do a Time Machine back-up in additon to the clone before installing ML
should I make a new clone of the internal HD with ML installed after checking all is ok, and then reformat the partion again to wipe out the SL clone for the ML clone?
because I am doing all this for the first time should I fork out the money for CCC or SuperDuper to make these clones and just use TM for incremental back-ups
Do I need to do a complete back-up with TM after installing ML?

if I need to delete all the data on the internal drive to install ML
No you dont, you can install straight over Snow leopard, unless tyou wish to do a clean install

do I need to do a Time Machine back-up in additon to the clone before installing ML
No, but it wont hurt to have both backups

should I make a new clone of the internal HD with ML installed after checking all is ok, and then reformat the partion again to wipe out the SL clone for the ML clone?
I would just go for a time machine backup once Mountain Lion is installed

because I am doing all this for the first time should I fork out the money for CCC or SuperDuper to make these clones and just use TM for incremental back-ups
Time machine is perfectly capable of restoring your mac should anything happen

Do I need to do a complete back-up with TM after installing ML?
Let Time machine be your backup once you have everything installed